1. Field of the Invention
The present invention relates to a receiver and a receiving method for synthesizing signals received by a plurality of antennas.
2. Related Art
In a terrestrial digital broadcast using an OFDM (Orthogonal Frequency Division Multiplexing) scheme, there is a request in which it is desirable to receive high-definition broadcast to be received by a fixed equipment even in a mobile object such as a vehicle. In order to fulfill such a request, as a technique of improving the received quality of the mobile object, there has been known a directional control technique using multiple antennas (see Japanese Patent Laid-open Pub. No. 2003-51768 and “a method relating to a directional control manner on reception of the terrestrial digital broadcast under mobile environment”, Information Processing Societies, 2003-ITS-15).
According to the receiver described in the above non-patent document, weighted coefficients different from each other are given to the signals received by multiple antennas to perform a weighted processing, and then a synthesized processing is performed.
On the other hand, according to a receiver described in the above patent document, S/N ratios of the respective signals received by multiple antennas are detected to select a signal having the most excellent S/N ratio.
There is an advantage in which a reception scheme of the above non-patent document can eliminate an interfering wave in Gaussian form. Contrary, when a part of a plurality of received paths connected to multiple antennas does not normally operate due to some reason, there is a disadvantage in which a signal quality of a synthesized signal lowers due to the influence.
On the other hand, the reception scheme of the above patent document has an advantage in which even if a part of a plurality of received paths does not normally operate, if at least one of a plurality of received paths normally operates, the most suitable received result is obtained. Contrary, according to the above patent document, there is a disadvantage in which if the received status of all the received paths is not good, the reception quality deteriorates extremely.